pycharm安装pytube工具包，可以参考github：https://github.com/nficano/pytube

from pytube import YouTube
link = input("enter link of youtube vadio:")
yt = YouTube(link)
videos = yt.streams.filter(subtype='mp4').all()

i = 1
for stream in videos:
    print(str(i) + " " + str(stream))
    i += 1

stream_number = int(input("enter number:"))

video = videos[stream_number-1]
# vadio文件夹必须存在，否则报错
video.download("D:/vadio")
print("downloaded")

 

控制台操作：
enter link of youtube vadio:https://www.youtube.com/watch?v=BH7D2aLPekc 
1 <Stream: itag="22" mime_type="video/mp4" res="720p" fps="30fps" vcodec="avc1.64001F" acodec="mp4a.40.2">
2 <Stream: itag="18" mime_type="video/mp4" res="360p" fps="30fps" vcodec="avc1.42001E" acodec="mp4a.40.2">
3 <Stream: itag="136" mime_type="video/mp4" res="720p" fps="30fps" vcodec="avc1.4d401f">
4 <Stream: itag="135" mime_type="video/mp4" res="480p" fps="30fps" vcodec="avc1.4d4014">
5 <Stream: itag="134" mime_type="video/mp4" res="360p" fps="30fps" vcodec="avc1.4d401e">
6 <Stream: itag="133" mime_type="video/mp4" res="240p" fps="30fps" vcodec="avc1.4d400c">
7 <Stream: itag="160" mime_type="video/mp4" res="144p" fps="30fps" vcodec="avc1.4d400b">
8 <Stream: itag="140" mime_type="audio/mp4" abr="128kbps" acodec="mp4a.40.2">
enter number:1
downloaded